Showing papers in "Journal of Bacteriology in 1942"

A New Type of Glucose Fermentation by Clostridium thermoaceticum

Abstract: The thermophilic fermentation of cellulosic material is generally regarded -as a result of the combined action of several species of bacteria, some of which attack the cellulose and others the sugars formed from the breakdown of the cellulose. Much effort has been spent on attempts to isolate the cellulose fermenters but very little attention has been paid to the associated sugar-fermenting organisms. Snieszko and Kimball (1933) isolated and described two types of such bacteria but gave no chemical data on the fermentation products formed. It, therefore, seemed desirable to make such a study.

Validity of the Genus Alcaligenes

Abstract: A recent paper by Conn, Wolfe and Ford (1939) discussed the question as to whether certain soil bacteria are related to the genus Alcaligenes as recognized in recent editions of Bergey's Manual of Determinative Bacteriology. So far as concerns the relationships between the soil bacteria and plant parasites discussed in that paper, the reasoning still seems sound. In one or two particulars, however, modification of the conclusions seems necessary in light of further evidence that has been obtained. This evidence relates to the identity of the type species, Alcaligene,s faecali. The statement was made in that paper: \"Apparently, therefore, there is a commonly recognized organism to which the name Alcaligenes faecalis can be assigned.\" Evidence is now at hand which makes that statement doubtful. Before presenting this evidence, however, a few words are necessary as to the history of this name, and of the specific designation.

Clostridium kluyverii, an Organism Concerned in the Formation of Caproic Acid from Ethyl Alcohol

Abstract: When ethyl alcohol is acted upon by the methane-producing organism, Methanobacterium omelianskii, acetic acid is the sole oxidation product (Barker (1939-40, 1941)). But with alcoholcontaining enrichment cultures for the same organism it often happens that acetic acid is formed in only relatively small amounts, while most of the alcohol is converted into caproic and butyric acids (Barker (1937)). In some cultures as much as 75 per cent by weight of the volatile acid is caproic. Microscopic examination has shown that such caproic-acidproducing enrichment cultures always differ from those forming only acetic acid by containing, besides M. omelianskii, considerable numbers of a large, motile, spore-forming bacterium. The conclusion seemed justified that this latter organism either itself produces or at least helps to produce the caproic acid. However, direct proof of the participation of the spore-forming bacterium in caproic acid formation can be obtained only by studying the organism in pure culture. This communication describes the isolation, the general morphological and physiological characteristics and certain growtlh requirements of this bacterium. Also, evidence is presented which demonstrates that it is responsible for the conversion of ethyl alcohol to caproic acid. Enrichment and isolation. To obtain the caproic acid-producing organism, Clostridium kluyverii,1 the following enrichment medium (no. 1) made with tap water is used: C2H5OH 1 vol. per cent; K2HPO4 0.5 per cent; MgSO4 7H20 0.01 per cent; (NH4)2 SO4 0.03 per cent; FeSO4 .77H20 0.002 per cent; yeast autolysate 0.5

Preparation and Properties of the Amylases Produced by Bacillus macerans and Bacillus polymyxa.

Abstract: The history of the Aerobacillus group has been reviewed by Porter, McCleskey, and Levine (1937), who compared all the available "species" and concluded that there were really only two, A. macerans and A. polymyxa; of the five earlier recognized by Donker (1926), two, A. vtolaris and A. amaracrylus, were no longer available for study, and a third, A. acetoethylicus Northrop, could not be differentiated from A. macerans. Porter and his co-workers agreed with Donker that A. asterosporus was identical with A. polymyxa. They accepted Donker's description of the genus Aerobacillus which has priority over that of Pribram (1933) and includes spore-forming rods which grow aerobically and anaerobically and decompose a great number of carbohydrates, including starch and glycogen, with production of carbon dioxide and hydrogen. The Aerobacillus group has now been made a subgenus of the genus Bacillus (1939), hence the latter is the correct genus name. Bacillus macerans and B. polymyxa are very similar morphologically and physiologically and have similar habitats, occurring in decaying vegetables and in soil and water. Porter, McCleskey, and Levine differentiated them in four ways: (1) by their behavior in the Voges-Proskauer test, in which B. macerans gave a negative and B. polymyxa a positive reaction, (2) by growth on media containing rhamnose and sorbitol, in which B. macerans produced acid and gas, while B. polymyxa did not, (3) by their optimal temperature range, which was higher for the B. macerans type, and (4) by serological reactions, B. macerans being a homogeneous antigenic type as distinct from the heterogeneous B. polymyxa type.

Growth Requirements of the Meningococcus.

Abstract: The meningococcus has been considered one of the more fastidious microorganisms with respect to growth requirements. Mueller and Hinton (1941) have shown, however, that excellent growth of this organism, as well as of the gonococcus, may be obtained on an agar medium containing only \"double strength\" meat infusion, casein hydrolysate, and starch paste. The purpose of the present investigation was to determine the essential factors in these mixtures.

Pseudomonas aeruginosa: Its Rôle as a Plant Pathogen.

Abstract: The idea that some organisms may have the ability to establish themselves and thrive within both plant and warm-blooded-animal tissues has received the attention of comparatively few workers. The vast gulf between the two forms of life, in structure, composition, and many environmental factors, has seemed to preclude the thought that both could be favorable hosts to the same organism. Nevertheless, attempts have been made to show that such a dual pathogenicity can occur. The most striking results were obtained by Benham and Kester (1932) using the fungus Sporotrichum. Employing strains isolated from both animals and plants, they found a few which would attack members of both kingdoms. The organism, S. schenckii, causing the human disease was transmitted to carnation and rose buds producing a rot similar to that caused by S. poae. After living saprophytically or parasitically in plants, S. schenckii retained its virulence for animals. In order to insure infection, however, it was necessary to provoke some slight injury before or at the time of the fungus injection. Ciferri and Baldacci (1934) inoculated 22 human pathogenic fungi and one insectivorous fungus into tomato fruits and found 18 that gave positive infection. They considered that their work not only confirmed that of Benham and Kester, but furnished additional evidence as regards the adaptability of human pathogens to plant hosts. With bacterial pathogens less positive results have been obtained. Baldacci and Ciferri (1934) found two of 23 organisms of human source able to produce some evidence of infection in tomato fruits. These organisms were Proteus vulgaris and Bacillus pyocyaneus. In neither case was the infection severe, nor did it approach the type usually associated with the apical rot of this fruit. Pseudomonas aeruginosa (B. pyocyaneus) has been a recognized human pathogen for a good many years. Its most distinguishing feature is the formation of the diffusible, chloroform-soluble, blue pigment, pyocyanin. This organism is widely distributed in nature, usually as a harmless saprophyte. On occasion, however, it can become a dangerous pathogen. Generally, it appears as a secondary invader and is often associated with suppurative lesions of various parts of the body. There are, nevertheless, numerous instances wherein it has been shown to be the primary cause of a fatal infection in man and other animals. Experimentally many domestic animals, rabbits, goats, mice, and guinea pigs are susceptible to infection. The animal pathogenicity of the organism is, therefore, a well established fact.

A Note on Elasticotaxis in Myxobacteria.

Abstract: When myxobacteria of the family Myxococcaceae are grown on agar slants, a striking abnormality in the production of fruiting bodies is often apparent. The fruits formed along the line of inoculation are not scattered at random, but are definitely oriented in roughly parallel lines at right angles to the line of inoculation. Sometimes each line is composed of a series of the usual discrete, approximately spherical fruiting bodies, but in other cases the individual fruits become confluent, so that a ridge of microcysts is formed. Due to the spread of the vegetative swarm, fruits are also ultimately formed on the agar surfaces on either side of the line of inoculation; such fruits always exhibit the customary random distribution and normal shape. In fig. 1 is shown a slant culture of Myxococcus fulvus which illustrates this phenomenon. It was first observed in this species, but is also exhibited by all the other members of the Myxococcaceae which I have studied. In seeking for an explanation of this behavior, it was at once apparent that chemical stimuli could not be invoked, since they would also have affected the fruiting process as it occurred in the regions of the slant surface away from the line of inoculation. The only conceivable difference between the streaked and unstreaked areas of the agar was a physical one. Accordingly, a series of experiments was performed in order to clarify the nature of the physical forces involved.

Agar-Decomposing Strains of the Actinomyces Coelicolor Species-Group.

Abstract: The ability to decompose agar has not hitherto been recorded for any member of the Actinomycetales, and consequently it seemed desirable to make a detailed study of a typical Actinomyces possessing this property, which was discovered fortuitously. The organism appeared on a discarded tapwater agar plate (used originally for the germination of myxomycete sclerotia) in the form of blue-black colonies with scanty greyish-white aerial mycelium, each of which lay in the center of a marked depression in the agar. Several strains were isolated and purified by repeated streaking on mineral agar plates with (NH4)2SO4 as a nitrogen source. The behavior of the pigment produced (blue under basic, red under acid conditions) marked the organism at once as a member of the widespread soil group of litmus actinomycetes, which are classified in Bergey's Manual under the name A. coelicolor. In response to my request, Dr. S. A. Waksman very kindly provided me with an authentic culture of this species from his collection, together with several agar-decomposing strains which had been isolated at the New Jersey Agricultural Experiment Station in the course of other work. These cultures (NB strains) together with my own isolates (PG strains) comprised the material for the following studies.

Selective Antibiotic Action of Various Substances of Microbial Origin.

Abstract: Since Pasteur first demonstrated that certain micro6rganisms are able to exert antagonistic or antibiotic effects upon other organisms, an extensive literature has accumulated (Waksman, 1941). The presence of living organisms is often necessary for the phenomenon of antagonism to take place. In many cases, the antagonist was found to produce an active substance responsible for this action. The active agent has been isolated, purified, and crystallized only in very few instances. Pyocyanase was the first antagonistic substance to have thus been obtained (Emmerich and Low, 1899). Several others have been isolated recently. Certain facts have now become recognized concerning the nature of the phenomenon produced by antagonistic microorganisms: 1. The various active substances isolated from the different organisms vary considerably in their chemical nature; 2. these substances are selective in their action upon various organisms, showing variation even as regards specific types or strains of the different groups of bacteria acted upon; 3. the substances vary in the mechanism of their action, some being primarily bacteriostatic, and others bactericidal but not bacteriolytic, whereas still others are both bactericidal and bacteriolytic; 4. the antagonistic capacity is widely distributed among microorganisms and is not limited to any one group of bacteria or fungi. Active antibiotic agents have now been obtained from representative types of spore-forming bacteria, non-spore-forming bacteria, actinomycetes and fungi. Some of these agents have not yet been isolated in a pure state; however, they are well recognized, both chemically and biologically, and can be characterized by their specific properties. The following substances or preparations have received the greatest consideration: 1. pyocyanase, 2. pyocyanin, 3. gramicidin, 4. tyrocidine, 5. penicillin, 6. gliotoxin, 7. actinomycin, and 8. streptothricin. The first four are of bacterial origin, the next two are produced by fungi, and the last two by actinomycetes. To these may be added several other preparations, of which the exact chemical nature or mode of action is less known, namely, actinomycetin, prodigiosin, fluorescin, microbial-lysozyme, active substances obtained from species of Aspergillus and from various other fungi and bacteria. Among the antagonistic phenomena which are now well recognized but for which no active substance has as yet been demonstrated, one may men-

The Source of Infection in Actinomycosis.

Abstract: There are two theories regarding the source of infection in actinomycosis. The exogenous theory introduced by Bostroem (1891) was based upon the fact that he observed awns of grass or gram' in the actinomycotic lesions of man and cattle. This theory has been propagated and enlarged upon by numerous authors but has gained support mainly from clinical observations. The endogenous theory did not receive recognition until relatively recent times, although supporting evidence can be found throughout the literature on actinomycosis. Lord (1910) noticed the occasional presence of organisms in sputum having the morphology of actinomycetes. By means of smears and sections, he also demonstrated actinomycetes in the contents of 16 carious teeth. Naeslund (1925) cultivated anaerobic actinomycetes from the oral cavity and stated that these organisms were nearly identical culturally with the anaerobic forms cultivated from cases of actinomycosis. Naeslund (1931) was unsuccessful in his attempt to produce experimental actinomycosis in animals with strains of anaerobic actinomycetes isolated from the oral cavity. Emmons (1935) cultivated anaerobic strains of actinomycetes from the oral cavity which resembled both culturally and morphologically the typical Actinomyces bovis. In 1936 and 1938 he cultured tonsils and obtained several strains of actinomycetes. These tonsillar strains were avirulent for guinea pigs. Lord and Trevett (1936) isolated 4 strains of anaerobic actino-

The Significance of the Large Bodies and the Development of L Type of Colonies in Bacterial Cultures.

Abstract: s of Communications, p. 21. DIENES, L. 1939a \"L\" organism of Klieneberger and Streptobacillus moniliformis. J. Infectious Diseases, 69, 24-42. DIENES, L. 1939b L type variant forms in cultures of various bacteria. Proc. Soc. Exptl. Biol. Med., 42, 636-640. DIENES, L. 1939c A peculiar reproductive process in colon bacillus colonies. Proc. Soc. Exptl. Biol. Med., 42, 773-778. DIENES, L. 1940a Origin of L type colony in bacterial cultures. Proc. Soc. Exptl. Biol. Med., 43, 703-724. DIENES, L. 1940b L type growth in gonococcus cultures. Proc. Soc. Exptl. Biol. Med., 44, 470-471. 61

An Improved Medium for the Cultivation of Hemolytic Streptococcus

Abstract: In the preceding paper (Bernheimer and Pappenheimer, 1942) the factors necessary for massive growth of group A hemolytic streptococcus on a medium of essentially defined chemical composition were discussed. The medium has been adapted for heavy growth in large volumes. Although worked out specifically for the C203S strain, the medium has proved useful for the cultivation of other strains of group A streptococcus. The following solutions are prepared:

Observations on Some Biological Characteristics of Organisms of the Pleuropneumonia Group

Abstract: Within the past few years there has arisen a renewed interest in that group of bacterial forms designated as the \"Pleuropneumonia Group,\" the prototype of which is Pleuropneumonia bovum, first described by Nocard and Roux in 1898, and for many years regarded as a virus because of its filterability. However, the cultivation of this organism on cell-free media, and the later complete description of a similar form as causing agalactia of sheep (Bridre and Donatien, 1925) removed them from this category. Of recent years the group has increased in number with some 20 different pleuropneumonia-like microorganisms being reported from highly varied sources. The common features which in general separate the pleuropneumonia organisms from the larger bacterial forms and filterable variants of the latter are: (1) A slow rate of growth, optimum for some strains being attained only after 4 to 6 days; (2) they require a high, 10-20 per cent, content of animal protein in the form of serum, etc., in the medium; (3) they stain poorly with the common aniline dyes but are well colored by the polychromatic stains, such as Giemsa; (4) morphologically they may exhibit a complex developmental cycle with asteroid, branching or granular forms being the predonminating elements. Although no exact determinations of their size have been made, the ability of these

The Production of Active Resting Cells of Streptococci.

Abstract: Nearly all of the recent studies relating to the nutrition of microorganisms have been directed toward raising the largest possible cell crop in a medium of known chemical composition, without regard to the physiological activity of the cells harvested from the medium. The purpose of the present study has been to produce resting cell suspensions of streptococci with sufficient activity and stability to permit metabolic studies. In this first attempt to obtain highly active cells, knowledge of the chemical composition of the medium has been sacrificed. It should not be too much to expect, however, that it will be possible to raise, in media of known composition, cells of high physiological activity. A number of reports in the literature, including those of Farrell (1935) and Callow (1926) indicate the difficulties encountered in the preparation of physiologically active suspensions of streptococci.

The Technique of Quantitative Chorioallantoic Virus Titration.

Abstract: Although the quantitative "pock counting" method of titrating a wide variety of viruses on the chorioallantois has been used in this laboratory for the last six years, there has been very little application of the method elsewhere. Schaffer and Enders (1939) studied the inactivation of herpes virus by immune serum along these lines and found the method satisfactory. Nelson (1938) has used the technique in roughly quantitative form for work with vaccinia and variola viruses. Haagen (1940) on the other hand considers that the method is quite unsuited for use as a general method for vaccinia virus titration. In the course of work on the photodynamic inactivation of herpes and vaccinia viruses with methylene blue we have attempted to improve several aspects of the technique. In essentials our present methods are the same as those described by Burnet in 1936 but attention to details has resulted in a considerable improvement in the membranes obtained. In our experience there is only one important cause for unsatisfactory results; this is haemorrhage on the inoculated surface of the chorioallantois. A large haemorrhage will cause death of the embryo within 24 hours while smaller ones are almost invariably associated with nonspecific lesions of the ulcer type as described in the 1936 monograph. There seems to be an irregular seasonal variation in the readiness with which haemorrhages occur, the late summer being generally the most unsatisfactory period. There are also smallperiod fluctuations, some weeks' supplies of eggs giving noticeably more satisfactory results than others. We have not been able to control the occurrence of these variations and can only suggest tentatively that they may be related to the nutrition of the laying hens; the possibility that the level of vitamin K may be responsible for the variation might be worth studying. Irrespective of the intrinsic character of the eggs supplied, the incidence of haemorrhage is largely determined by the care with which the various manipulations incidental to the inoculation are carried out. Haemorrhage may result from the trauma of a drill cut involving the shell membrane, from the turning in of a pointed angle as the triangle of shell is removed or from damage produced when the slit is made in the shell membrane in the first stage of inoculation. The capillaries from which haemorrhage occurs lie very superficially in direct contact with the inner surface of the shell membrane and haemorrhage may also be produced in the process of separating the chorioallantois and shell membrane. The only important modification of technique which we have recently introduced is designed to minimize damage during separation. This is to draw in a drop of sterile saline to act as a fluid wedge and make the falling

Bacteria Attacking Petroleum and Oil Fractions

Abstract: Although a number of workers have reported that certain bacteria and molds are capable of attacking hydrocarbons and mineral oils it is still not generally recognized how widespread is the occurrence of these organisms nor how great a variety of compounds of this nature may be attacked. Since S6hngen (1906) showed that some microorganisms possess the ability to utilize methane and Rahn (1906) described molds capable of attacking paraffin, there have appeared about thirty papers on the subject (cf. Hessel, 1924, and Tausson, 1929). Various gram-negative rods, particularly Pseudomonas, mycobacteria and micrococci have been described as attacking petroleum but there has been little effort made to compare organisms having this ability with bacteria that obtain their growth energy from the ordinary sources. Recently Bushnell and Haas (1941) have studied hydrocarbon utilization by various organisms and have found that Pseudomonas strains are most active whiJe certain species of micrococci and corynebacteria are also able to assimilate these compounds. The conditions necessary for attack on oils by microorganisms have been summarized by Tausson (1928) as follows: (1) presence of water with mineral salts; (2) a nitrogen source, such as the ammonium or nitrate ion; (3) free access of oxygen; (4) a neutral reaction and a buffer such as CaCO3 to maintain it. However, there has been little attention given as to what hydrocarbons are most subject to attack and the mechanism of their breakdown, although Tausson and co-workers (1934) have shown that some acids and unsaturation are produced in the bacterial dissimilation of crude and lubricating oils. The purpose of this work was to determine how wide a range of petroleum fractions could be readily attacked, to attempt to find which of several representative petroleum fractions were most subject to attack, and to isolate and characterize a number of organisms able to develop on a hydrocarbon medium.

Studies on the Antibacterial Factors of Human Saliva.

Abstract: In previous studies it was found that the growth of 110 of 169 strains of bacteria tested was prevented by human saliva (Bibby, Clough and Hine, 1938). This effect was more marked against some types of organisms than against others, those most affected being bacilli and cocci isolated from air and water; those least affected, organisms isolated from the mouth. Differences occurred in the inhibitory potency of saliva from individual to individual and from time to time. Dissimilarities were noted between the agent effective against Micrococcus lysodeikticus and that acting on strains of lactobacilli, streptococci, and staphylococci. The former activity was removed by Berkefeld-N filtration and appeared to be more closely associated with oral bacteria and the presence of epithelial cells. Our suggestion that there are two distinct antibacterial agents in the saliva is supported by Thompson who has summarized the evidence in an excellent review (1940) and shown (1941) differences in the properties of salivary lysozyme and another antibacterial factor in the saliva. The present study was designed to establish more definitely whether there is more than one antibacterial agent in saliva and, if so, to investigate the properties of such agents. To this end saliva was subjected to various treatments before testing against susceptible bacteria. Tests were made of its mode of action on different organisms and attempts at concentration and purification of the agents were undertaken.

Growth Requirements of Clostridium tetani.

Abstract: Information as to the chemical nature of substances concerned in the nutrition of pathogenic bacteria has been rapidly accumulating in the past five years. Aerobic types, particularly, have been studied, and while there remains much to be done the general scheme of affairs has been pretty well laid out. In general, the strictly anaerobic organisms have received less attention. Except for the publications of Fildes and his colleagues (Fildes and Knight, 1933) and of Pappenheimer (1935) on the \"sporogenes vitamin,\" very little experimental work has appeared. The increasing use of tetanus toxoid in prophylactic immunization brings this organism especially into the foreground. Such fundamental advances have been possible in the production of diphtheria toxin as a result of nutritional studies (Mueller and Miller, 1941) that one may venture to hope for a similar result in the case of tetanus. The routine production of this anaerobic toxin has until now been attended by the same difficulties as were met in the case of diphtheria toxin. Moreover, the longer intervals recommended in the use of tetanus toxoid, and the necessity for \"recall\" doses, may be expected to result in reactions of anaphylactic type in certain individuals when toxoid prepared on peptone, particularly Witte's peptone, is employed. If it were possible to grow the tetanus organism on a medium containing only chemically defined substances of low molecular weight, it should become a relatively straightforward matter to

Studies on the Luminous Bacteria: I. Nutritional Requirements of Some Species, with Special Reference to Methionine.

Abstract: Anyone who has had occasion to isolate luminous bacteria can readily understand why these organisms have received so much attention from microbiologists of the present and of the last centuries The aesthetic satisfaction derived from the contemplation of these beautiful organisms repays the investigator many fold for the hours spent in darkness and seclusion vis a vis some fetid putrefying fish. Due partly, no doubt, to this fact, a voluminous literature dealing with these bacteria has accumulated. For an excellent bibliography and a review of all the most important contributions to the knowledge of the luminous bacteria and to the understanding of the physiology of luminescence, reference need only be made to Pratje (1923) and Harvey (1940, 1941). Owing to the recognition that the light-emitting process is a by-path of respiration, and to the convenience of using changes in the intensity of luminescence as an indicator of physiological events in the organisms, the luminous bacteria have acquired, in the last few years, a new importance in scientific research, as material for exceedingly interesting experiments on general physiological problems. (E.g., Johnson, 1938, 1939.) Little attention, however, has been devoted to the natural history of this group of bacteria since Beijerinck's studies (Beijerinck, 1889, 1912, 1916). Although innumerable species have been described, no thorough systematic study of the group has ever been undertaken with a view to clarifying their relationship among themselves or with other bacteria. In the hope of contributing to the elucidation of some of the complex taxonomic and physiological problems involved in the sudy of this group of organisms and to the better understanding of some previously recorded observations on the behavior of the bacteria under certain conditions, a series of investigations has been carried out on the nutrition and metabolism of several species, the results of which seem to be of sufficient general interest to warrant their publication. In the present paper, the results of experiments on growth requirements of a number of strains will be presented.

The Erwinia-Coliform Relationship.

Abstract: Erwinia, a genus of bacterial plant pathogens, has long been recognized as closely related to the Escherichia-Aerobacter group. This view, although readily accepted, has been the object of little comparative study; the relationship is usually taken for granted, the result being a relatively poor understanding of the similarities of the two groups. On the basis of its disease-producing ability in plants, Bergey et al. (1939) gives the group tribal ranking, Erwineae, in the family Enterobacteriaceae. Other than the obvious facts that the species of Erwinia are peritrichously flagellated, gram negative, do not form spores and ferment many carbohydrates, including lactose, our knowledge of the relationship is meager. The possibility that the Erwinial might be coliform organisms has been given comparatively little thought. Stuart et al. (1938, 1940) recognized the possibility of Erwinia cultures being confused with coliform organisms, or vice versa, and included some plant cultures in their studies. Stanley (1939) likewise declared the soft-rot group to belong to the colon-typhoid-dysentery group, and suggested that organisms identified as Erwinia might be Escherichia coli, the latter interpreted in a broad sense. According to Parr (1939), F. D. Chester stated that the genus Erwinia was established on a purely utilitarian basis and had no genetic standing. Dowson (1939), following the usual British practice, advocated the inclusion of the soft-rot pathogens in the genus Bacterium Lehmann and Neumann. By this procedure he recognized the apparent close relationship of the coliform and Erwinia groups, as the former are likewise placed in this genus. Unfortunately, the biochemical characteristics of the soft-rot organisms are as variable as those of coliform isolates (Stanley 1939, Elrod 1941). It has been shown, especially by Stanley, that fermentative shifts are common, tending to throw a culture from one species to another. These changes usually concern a change from an aerogenic to an anaerogenic state, although some variation has been noted in the methyl-red, Voges-Proskauer and citrate tests. Elrod (1941) found that the soft-rot group is as antigenicaily heterogeneous as the coliform group. In the light of our abundant knowledge of the coliform group, it was decided first to employ \"coliform\" methods in an attempt to arrive at a better understanding of the Erwinia-Escherichia-Aerobacter relationship. The recent work of Stuart, Mickle and Borman (1940) on aberrant coliforms offers a way of

The Cultivation and Nutrient Requirements of a Chytridiaceous Fungus, Rhizophlyctis rosea

Abstract: Although much work has been done in recent years on the morphology and development of the Chytridiales, information concerning the cultivation and nutrient requirements of these fungi is still very incomplete. Sparrow (1931) was the first to report success in growing a chytrid on an artificial medium. He cultivated Cladochytrium nowakowskii (according to Karling (1935) identical with Cladochytrium replicatum) on cornmeal agar for some time without, however, freeiing it from bacterial contaminants. Butler and Humphries (1932) obtained growth of Catenaria anguillulae, a parasite in the ova of the sheep liverfluke, on various decoctions of fluke ova extract. It is not clear from their report if pure cultures, were obtained; judging by the methods used, this seems unlikely. Karling (1935) attempted to grow Cladochytrium replicatum on a variety of substrates. Only on cornmeal agar and soil mannitol agar was fair growth obtained, but the production of zoosporangia was sparse and abnormal, indicating that the media were unsuitable. In this connection it is interesting to point out that Cladochytrium replicatum was one of the species which Haskins (1939) grew satisfactorily on cellulose. If Karling succeeded in getting a pure culture, which was not explicitly stated, he did not maintain it for long, since the chytrid was overrun after a month by yeasts.